C++ AP_GPS类代码示例

/*
  send raw GPS position information (GPS_RAW_INT, GPS2_RAW, GPS_RTK and GPS2_RTK).
  returns true if messages fit into transmit buffer, false otherwise.
 */
bool GCS_MAVLINK::send_gps_raw(AP_GPS &gps)
{
    if (comm_get_txspace(chan) >=
            MAVLINK_MSG_ID_GPS_RAW_INT_LEN + MAVLINK_NUM_NON_PAYLOAD_BYTES) {
        gps.send_mavlink_gps_raw(chan);
    } else {
        return false;
    }

    if (gps.highest_supported_status(0) > AP_GPS::GPS_OK_FIX_3D) {
        if (comm_get_txspace(chan) >= MAVLINK_NUM_NON_PAYLOAD_BYTES+MAVLINK_MSG_ID_GPS_RTK_LEN) {
            gps.send_mavlink_gps_rtk(chan);
        }

    }

    if (gps.num_sensors() > 1 && gps.status(1) > AP_GPS::NO_GPS) {

        if (comm_get_txspace(chan) >= MAVLINK_NUM_NON_PAYLOAD_BYTES+MAVLINK_MSG_ID_GPS2_RAW_LEN) {
            gps.send_mavlink_gps2_raw(chan);
        }

        if (gps.highest_supported_status(1) > AP_GPS::GPS_OK_FIX_3D) {
            if (comm_get_txspace(chan) >=
                    MAVLINK_NUM_NON_PAYLOAD_BYTES+MAVLINK_MSG_ID_GPS2_RTK_LEN) {
                gps.send_mavlink_gps2_rtk(chan);
            }
        }
    }

    //TODO: Should check what else managed to get through...
    return true;

}

/*
 @brief Generates pseudorandom ICAO from gps time, lat, and lon.
 Reference: DO282B, 2.2.4.5.1.3.2

 Note gps.time is the number of seconds since UTC midnight
*/
uint32_t AP_ADSB::genICAO(const Location_Class &loc)
{
    // gps_time is not seconds since UTC midnight, but it is an equivalent random number
    // TODO: use UTC time instead of GPS time
    AP_GPS gps = _ahrs.get_gps();
    const uint64_t gps_time = gps.time_epoch_usec();

    uint32_t timeSum = 0;
    uint32_t M3 = 4096 * (loc.lat & 0x00000FFF) + (loc.lng & 0x00000FFF);

    for (uint8_t i=0; i<24; i++) {
        timeSum += (((gps_time & 0x00FFFFFF)>> i) & 0x00000001);
    }
    return( (timeSum ^ M3) & 0x00FFFFFF);
}

/*
  send the SYSTEM_TIME message
 */
void GCS_MAVLINK::send_system_time(AP_GPS &gps)
{
    mavlink_msg_system_time_send(
        chan,
        gps.time_epoch_usec(),
        hal.scheduler->millis());
}

/*
  send the SYSTEM_TIME message
 */
void GCS_MAVLINK::send_system_time(AP_GPS &gps)
{
    mavlink_msg_system_time_send(
        chan,
        gps.time_epoch_usec(),
        AP_HAL::millis());
}

void 
GCS_MAVLINK::handle_gps_inject(const mavlink_message_t *msg, AP_GPS &gps)
{
    mavlink_gps_inject_data_t packet;
    mavlink_msg_gps_inject_data_decode(msg, &packet);
    //TODO: check target

    gps.inject_data(packet.data, packet.len);

}

/*
  send raw GPS position information (GPS_RAW_INT, GPS2_RAW, GPS_RTK and GPS2_RTK).
  returns true if messages fit into transmit buffer, false otherwise.
 */
bool GCS_MAVLINK::send_gps_raw(AP_GPS &gps)
{

    int16_t payload_space = comm_get_txspace(chan) - MAVLINK_NUM_NON_PAYLOAD_BYTES;
    if (payload_space >= MAVLINK_MSG_ID_GPS_RAW_INT_LEN) {
        gps.send_mavlink_gps_raw(chan);
    } else {
        return false;
    }

#if GPS_RTK_AVAILABLE
    if (gps.highest_supported_status(0) > AP_GPS::GPS_OK_FIX_3D) {
        payload_space = comm_get_txspace(chan) - MAVLINK_NUM_NON_PAYLOAD_BYTES;
        if (payload_space >= MAVLINK_MSG_ID_GPS_RTK_LEN) {
            gps.send_mavlink_gps_rtk(chan);
        }

    }
#endif

#if GPS_MAX_INSTANCES > 1

    if (gps.num_sensors() > 1 && gps.status(1) > AP_GPS::NO_GPS) {

        payload_space = comm_get_txspace(chan) - MAVLINK_NUM_NON_PAYLOAD_BYTES;
        if (payload_space >= MAVLINK_MSG_ID_GPS2_RAW_LEN) {
            gps.send_mavlink_gps2_raw(chan);
        }

#if GPS_RTK_AVAILABLE
        if (gps.highest_supported_status(1) > AP_GPS::GPS_OK_FIX_3D) {
            payload_space = comm_get_txspace(chan) - MAVLINK_NUM_NON_PAYLOAD_BYTES;
            if (payload_space >= MAVLINK_MSG_ID_GPS2_RTK_LEN) {
                gps.send_mavlink_gps2_rtk(chan);
            }
        }
#endif
    }
#endif

    //TODO: Should check what else managed to get through...
    return true;

}

/*
  Send camera feedback to the GCS
 */
void AP_Camera::send_feedback(mavlink_channel_t chan, AP_GPS &gps, const AP_AHRS &ahrs, const Location &current_loc)
{
    float altitude, altitude_rel;
    if (current_loc.flags.relative_alt) {
        altitude = current_loc.alt+ahrs.get_home().alt;
        altitude_rel = current_loc.alt;
    } else {
        altitude = current_loc.alt;
        altitude_rel = current_loc.alt - ahrs.get_home().alt;
    }

    mavlink_msg_camera_feedback_send(chan, 
        gps.time_epoch_usec(),
        0, 0, _image_index,
        current_loc.lat, current_loc.lng,
        altitude/100.0f, altitude_rel/100.0f,
        ahrs.roll_sensor/100.0f, ahrs.pitch_sensor/100.0f, ahrs.yaw_sensor/100.0f,
        0.0f,CAMERA_FEEDBACK_PHOTO);
}

/*
  send an initialisation blob to configure the GPS
 */
void AP_GPS_MTK::send_init_blob(uint8_t instance, AP_GPS &gps)
{
    gps.send_blob_start(instance, _initialisation_blob, sizeof(_initialisation_blob));
}

void AP_ADSB::send_dynamic_out(const mavlink_channel_t chan)
{
    // --------------
    // Knowns
    AP_GPS gps = _ahrs.get_gps();
    Vector3f gps_velocity = gps.velocity();

    int32_t latitude = _my_loc.lat;
    int32_t longitude = _my_loc.lng;
    int32_t altGNSS = _my_loc.alt*0.1f; // convert cm to mm
    int16_t velVert = gps_velocity.z * 1E2; // convert m/s to cm/s
    int16_t nsVog = gps_velocity.x * 1E2; // convert m/s to cm/s
    int16_t ewVog = gps_velocity.y * 1E2; // convert m/s to cm/s
    uint8_t fixType = gps.status(); // this lines up perfectly with our enum
    uint8_t emStatus = 0; // TODO: implement this ENUM. no emergency = 0
    uint8_t numSats = gps.num_sats();
    uint16_t squawk = 1200; // Mode A code (typically 1200 [0x04B0] for VFR)

    uint32_t accHoriz = UINT_MAX;
    float accHoriz_f;
    if (gps.horizontal_accuracy(accHoriz_f)) {
        accHoriz = accHoriz_f * 1E3; // convert m to mm
    }

    uint16_t accVert = USHRT_MAX;
    float accVert_f;
    if (gps.vertical_accuracy(accVert_f)) {
        accVert = accVert_f * 1E2; // convert m to cm
    }

    uint16_t accVel = USHRT_MAX;
    float accVel_f;
    if (gps.speed_accuracy(accVel_f)) {
        accVel = accVel_f * 1E3; // convert m/s to mm/s
    }

    uint16_t state = 0;
    if (out_state._is_in_auto_mode) {
        state |= UAVIONIX_ADSB_OUT_DYNAMIC_STATE_AUTOPILOT_ENABLED;
    }
    if (!out_state.is_flying) {
        state |= UAVIONIX_ADSB_OUT_DYNAMIC_STATE_ON_GROUND;
    }



    // --------------
    // Not Sure
    uint32_t utcTime = UINT_MAX; //    uint32_t utcTime,
    // TODO: confirm this sets utcTime correctly
    const uint64_t gps_time = gps.time_epoch_usec();
    utcTime = gps_time / 1000000ULL;



    // --------------
    // Unknowns
    // TODO: implement http://www.srh.noaa.gov/images/epz/wxcalc/pressureAltitude.pdf
    int32_t altPres = INT_MAX; //_ahrs.get_baro().get_altitude() relative to home, not MSL



    mavlink_msg_uavionix_adsb_out_dynamic_send(
            chan,
            utcTime,
            latitude,
            longitude,
            altGNSS,
            fixType,
            numSats,
            altPres,
            accHoriz,
            accVert,
            accVel,
            velVert,
            nsVog,
            ewVog,
            emStatus,
            state,
            squawk);
}

/**
   handle a SERIAL_CONTROL message
 */
void GCS_MAVLINK::handle_serial_control(mavlink_message_t *msg, AP_GPS &gps)
{
    mavlink_serial_control_t packet;
    mavlink_msg_serial_control_decode(msg, &packet);

    AP_HAL::UARTDriver *port = NULL;

    if (packet.flags & SERIAL_CONTROL_FLAG_REPLY) {
        // how did this packet get to us?
        return;
    }

    bool exclusive = (packet.flags & SERIAL_CONTROL_FLAG_EXCLUSIVE) != 0;

    switch (packet.device) {
    case SERIAL_CONTROL_DEV_TELEM1:
        port = hal.uartC;
        lock_channel(MAVLINK_COMM_1, exclusive);
        break;
    case SERIAL_CONTROL_DEV_TELEM2:
        port = hal.uartD;
        lock_channel(MAVLINK_COMM_2, exclusive);
        break;
    case SERIAL_CONTROL_DEV_GPS1:
        port = hal.uartB;
        gps.lock_port(0, exclusive);
        break;
    case SERIAL_CONTROL_DEV_GPS2:
        port = hal.uartE;
        gps.lock_port(1, exclusive);
        break;
    default:
        // not supported yet
        return;
    }

    if (exclusive) {
        // force flow control off for exclusive access. This protocol
        // is used to talk to bootloaders which may not have flow
        // control support
        port->set_flow_control(AP_HAL::UARTDriver::FLOW_CONTROL_DISABLE);
    }

    // optionally change the baudrate
    if (packet.baudrate != 0) {
        port->begin(packet.baudrate);
    }

    // write the data
    if (packet.count != 0) {
        if ((packet.flags & SERIAL_CONTROL_FLAG_BLOCKING) == 0) {
            port->write(packet.data, packet.count);
        } else {
            const uint8_t *data = &packet.data[0];
            uint8_t count = packet.count;
            while (count > 0) {
                while (port->txspace() <= 0) {
                    hal.scheduler->delay(5);
                }
                uint16_t n = port->txspace();
                if (n > packet.count) {
                    n = packet.count;
                }
                port->write(data, n);
                data += n;
                count -= n;
            }
        }
    }

    if ((packet.flags & SERIAL_CONTROL_FLAG_RESPOND) == 0) {
        // no response expected
        return;
    }

    uint8_t flags = packet.flags;

more_data:
    // sleep for the timeout
    while (packet.timeout != 0 &&
            port->available() < (int16_t)sizeof(packet.data)) {
        hal.scheduler->delay(1);
        packet.timeout--;
    }

    packet.flags = SERIAL_CONTROL_FLAG_REPLY;

    // work out how many bytes are available
    int16_t available = port->available();
    if (available < 0) {
        available = 0;
    }
    if (available > (int16_t)sizeof(packet.data)) {
        available = sizeof(packet.data);
    }

    // read any reply data
//.........这里部分代码省略.........

void setup(void)
{
    serial_manager.init();
    ins.init(100);
    baro.init();
    ahrs.init();

    gps.init(NULL, serial_manager);
}

void setup()
{
    hal.console->println("GPS AUTO library test");
    hal.console->println("Test Starting");
    // Initialise the leds
    board_led.init();

    // Initialize the UART for GPS system
    serial_manager.init();
    gps.init(NULL, serial_manager);
}

void loop()
{
    static uint32_t last_msg_ms;

    // Update GPS state based on possible bytes received from the module.
    gps.update();

    // If new GPS data is received, output it's contents to the console
    // Here we rely on the time of the message in GPS class and the time of last message
    // saved in static variable last_msg_ms. When new message is received, the time
    // in GPS class will be updated.
    if (last_msg_ms != gps.last_message_time_ms()) {
        // Reset the time of message
        last_msg_ms = gps.last_message_time_ms();

        // Acquire location
        const Location &loc = gps.location();

        // Print the contents of message
        hal.console->print("Lat: ");
        print_latlon(hal.console, loc.lat);
        hal.console->print(" Lon: ");
        print_latlon(hal.console, loc.lng);
        hal.console->printf(" Alt: %.2fm GSP: %.2fm/s CoG: %d SAT: %d TIM: %u/%lu STATUS: %u\n",
                            loc.alt * 0.01f,
                            gps.ground_speed(),
                            (int)gps.ground_course_cd() / 100,
                            gps.num_sats(),
                            gps.time_week(),
                            (unsigned long)gps.time_week_ms(),
                            gps.status());
    }
    else
    {
        hal.console->println("It seemed like NO GPS");        
    }

    // Delay for 10 mS will give us 100 Hz invocation rate
    hal.scheduler->delay(10);
}

//to be called only once on boot for initializing objects
void setup()
{
    hal.console->printf("GPS AUTO library test\n");

    board_config.init();

    // Initialise the leds
    board_led.init();

    // Initialize the UART for GPS system
    serial_manager.init();
    gps.init(serial_manager);
}

void setup(void)
{
    ins.init(100);
    ahrs.init();
    serial_manager.init();

    if( compass.init() ) {
        hal.console->printf("Enabling compass\n");
        ahrs.set_compass(&compass);
    } else {
        hal.console->printf("No compass detected\n");
    }
    gps.init(NULL, serial_manager);
}